Manufacture of electrical conductors



June 1932- J. M. G. FULLMAN ET AL 1,863,979

MANUFACTURE OF ELECTRICAL CONDUCTORS Filed June 4, 1928 2 Sheets-Sh et l June 21, 1932.

J. M. G. FULLMAN ET AL 1,

MANUFACTURE OF ELECTRICAL CONDUCTORS Filed June 4, 1928 2 Sheets-Sheet 2 by a new method which is and applying the jacket by around the opening 2 1s the base of the holr worm-wheel 18 on the short shaft 19 which Patented June 21, 1932 PQATENT OFFICE JAMES M. G. FULLMAN, OF SEWICKLEY, AN

SY'LVAINIA, ASSIGNORS, BY MESNE ASSI D LOUIS J.- RITTELMANN, or BADEN, PENN- GNMENTS, TO NATIONAL ELECTRIC PROD- UCTS CORPORATION, A CORPORATION OF DELAWARE g MANUFACTURE OF ELECTRICAL CONDUCTORS Application filed June 4, 1928. Serial No. 282,650.

It is the object of the present invention to produce an insulated electrical conductor having an insulating sheath or jacket of novel form which is applied to the conductor both eflicacious and economical.

In the accompanying drawings Figure l is a view in elevation of an apparatus which has been found to be suitable for forming the method to be presently described. Figure 2 is a plan view of the table and the supply reels. Figure 3 is an enlarged sectional elevation of the combined coiling and compressing die. Figure 4 is a view in cross-section on the line IVIV of Figure 3. Figure 5 is a crosssection on the line VV of Figure 3. Figure 6 is a view in elevation showing the conductor with successive layers of its cov ering cut away in order to show the interior construction.

The tablel is rotatably mounted on a supporting frame and has a central opemng 9 Secured to the upper face of the table low spindle'3 which carries at its top the die 4 to be hereinafter described. Symmetncally disposed around the central spindle 3 i are the radially arranged reels 5 having journals 6 rotatably mounted in bearings 7 mounted upon the upper face of the table. Secured centrally to the under face of the table in line with-the opening low sleeve 8 carrying the bevel gear 9, which meshes with a bevel pinion 10 on the transverse shaft 11, which carries at its outer end the fast and loose pulleys 12 and 13 for con: nection with the source of power. The shaft 11 also has secured to it near its outer enda second bevel pinion 14 which meshes with the bevel pinion 15 on the vertical shaft 16. Se cured to the upper portion of the shaft 16 is the worm 17 meshing with and driving a carries the gear-wheel 20 meshing with the pinion 21 on the upper transverse shaft 22. The shaft 22 also carries the pinion 23, which is connected through the intermediate pinion 24 with the circumferential teeth -25 on one edge of the surface of the capstan 26,

2 is the hol-- which several are well known, for the performance of that function.

The material used for the insulating sheath or jacket of the conductor is a fibrous material which is initially suppliedv in the form of long strips, is then crumpled transversely 'into a continuous loose and compressible bundle which is wound about the conductor in a continuous series of helical coils, and such compressible helical coils finally are compressed tightly upon the surface of the conductor in such manner that the successive convolutions are caused to overlap and interlock, so thatthere is supplied a very tightly compressed and uniform insulating jacket or sheath on the conductor.

The fibrous insulating material which we prefer for this purpose is paper. Strips of the paper to be used are wound upon the reels 5 and are drawn from these reels into and through the die 4, as shown in Figures 1, 2 and 3. The die 4 is a sleevelike structure supported on the top of the hollow spindle 3 bythe-legs- 30. Its lower portion 31 has a bore somewhat larger than the conductor to be jacketed, while its upper portion 32 isof such reduced size as to operate to compress and iron down the successive coils which are applied to the conductor as it passes through the lower portion 31.. In

the wall of the portion 31 are formed openings 33 arranged in line with the respective since the closely contacting helical coils upon the con= ductor as it is being drawn through the die.v As these bundled compressible coils are Wound upon the conductor, the conductor and coils are drawn on through the constricted cylindrical portion 32 of the die and the coils are ironed out and tightly compressed upon the surface of the conductor. In this operation-a portion'of each coil inadvance is necessarily pressed down in overlapping contact with the immediately following portion of the jacket, and by reasonof the crumpled and irregular formation of the compressible coils they engage with one another bodily in interlocking folds, so that finally the compressed coils form what is substantially 'a continuous unitary jacket, with the effect that, no matter upon how short a radius the jacketed conductor may be bent, there will be no separation or break in the substance of the jacket, but it will'continue to be a substantially integral structure.

We have shown in Figure 6 of the drawings an elevation of the jacketed conductor with successive layers of its covering cutv away, in order to show the interior construction. In this figure the conducting wire is indicated by the numeral 35. Upon this wire there has been applied the usual inner insu-' lating rubber jacket 36, and around this rubber jacket there has been formed the woven or braided fibrous covering 37 In the practice of the present invention the conductor, consisting of the wire, the rubber insulation and the enveloping fibrous covering, is sup plied from the reel 27 and is covered with the compressed fibrous insulating jacket 38, as herein described. Subsequently the completed jacketed conductor may be drawn through a bath of water-proofing compound, as is usual, and may then be utilized in any of theways 'well known in the art.

It will of course be understood thatin the specific mechanism herein shown and described, the driving elements will be so arranged and proportioned relatively to one another, that the speed of rotation of the capstan 26 will be so related to-the speed of rotation of the table and the die as to coil the crumpled paper strips upon the conductor in the most effective arrangement and sequence of coils. But it will also be understood that the present invention is not limited to the employment of any specific apparatus, method of manufacture herein de scribed andclaimed may be practiced by the use of apparatus of a variety of forms. In case the mechanism used should be of such character as to twist the strips, in addition to transversely crumpling them, the twist should be aloose one, so as not to substantially afiect the softness or compressibility of thecrumpled strands.

While we have herein shown and described the coiling of four crumpled strips uponthe' neath.

conductor, the invention is not limited to the employment of any particular number of strips, and one strip alone, of proper texture and size, may be utilized with good results. However there is an advantage in using a plurality of strips as shown, in that if one ofthe strips should break, as will sometimes happen, no serious harm will be done until this break shall berepaired', since the continuity of the insulating jacket will not be broken. The coils as wrapped around the conductor may relation or they may be non-overlapping. In the latter case the operation of compression will cause them to overlap and become united to form a continuous jacket, and in either case the product of the compression will be a uniform continuous jacket.

The surface of the completed insulating jacket is substantially smooth and uniform,

- and its structure is such as to eflectively pre- Zvent leakage throu h it of any of the combe in more or'less overlapping pounds which may e employed, and conse quent discoloration of the abric layer under- We-claim as our invention: 1. The method herein described which comprises transversely crumpling a flat strip of fibrous insulating material into a soft, compressible strand,wrapping the strand upon an electrical conductor in a succession of helical, non-overlapping coils, and compressing the coils tightly upon the conductor and upon adj acent coils thus formin continuous insulating jac conductor. v

2. The method herein described which comprises transversely crumpling a flat strip of paper into a soft, compressible strand, wrapping the strand upon an electrical conductor in a succession of helical, non-overlapping coils, and compressing the coils et enclosing the a smooth-surfacetightly upon the conductor and upon adja- 

